1. Field of the Invention
The present invention relates to a biological information detecting device.
2. Description of the Related Art
There exist biological information detecting devices detecting a biological signal by allowing a sensor electrode to contact a biological surface. In this kind of biological information detecting devices, there is the one which measures a heart rate from the biological surface, for example, by detecting an electrocardiographic signal generated by heartbeats by the sensor electrode. As such biological information detecting device, there is the one including a pair of electrode portions and a device body transmitting an electrocardiographic signal detected by the electrode portions to the outside as disclosed in Japanese Patent No. 4439856 (Patent Literature 1). The device body is electrically connected to the pair of respective electrode portions by wires. Each of the pair of electrode portions includes a hook for holding the electrode portions at prescribed sites of the body by sandwiching a garment or the like mounted to a body. Then, the pair of electrode portions are pressed toward the biological surface by the garment and so on.
There is also disclosed a structure in which an attachment belt for holding the electrode portions at prescribed sites of the body is separately prepared instead of the garment and so on in Patent Literature 1 described below. In the attachment belt, a cut for receiving the hook is formed, which prevents displacement of positions of the electrode portions with respect to the attachment belt.
The heart rate is measured by detecting the electrocardiographic signal generated by heartbeats by the pair of electrode portions under the above structure.
However, in the case where the electrode portions are held by sandwiching the garment or the like by the hook in the above related art, it is difficult to obtain sufficient holding force with respect to the electrode portions only by sandwiching force of the hook. Accordingly, there are problems that pressing force of the electrode portions onto the biological surface is reduced when the electrode portions are displaced or removed from the garment or the like due to a moving manner of a wearer, which may hinder good detection of an electrocardiographic signal.
On the other hand, when the electrode portions are held by inserting the hook into the cut in the attachment belt or the like, the pressing force of the electrode portions onto the biological surface is not reduced as the positions of the electrode portions with respect to the attachment belt is not displaced. However, when the attachment belt is stretched/contracted along an extending direction so as to follow the movement of the wearer, the positions of the electrode portions are displaced so as to follow the stretching/contracting movement of the attachment belt. Accordingly, there is a problem that contact positions of the electrode portions with respect to the biological surface are not stable, which hinders good detection of an electrocardiographic signal. There is also a danger of disconnection and so on as the wires of the electrode portions are pulled along the extending direction of the attachment belt due to the stretching/contracting movement of the attachment belt.